Add copyright notices to source file headers

[nam20485]

With a reference to the LICENSE

/*
 * Copyright (c) 2023 Nathan Miller <nmiller217@gmail.com>
 *
 * OdbDesign is free software; you can redistribute it and/or modify
 * it under the terms of the MIT license. See LICENSE for details.
 */

// Copyright (c) 2023 Nathan Miller <nmiller217@gmail.com>
//
// OdbDesign is free software; you can redistribute it and/or modify
// it under the terms of the MIT license. See LICENSE for details.